diff --git a/example/lib/src/register.dart b/example/lib/src/register.dart
index 3081c0bb..9afd1a76 100644
--- a/example/lib/src/register.dart
+++ b/example/lib/src/register.dart
@@ -136,6 +136,7 @@ class _MyRegisterWidget extends State<RegisterWidget>
     settings.displayName = _displayNameController.text;
     settings.userAgent = 'Dart SIP Client v1.0.0';
     settings.dtmfMode = DtmfMode.RFC2833;
+    settings.contact_uri = 'sip:${_sipUriController.text}';
 
     helper!.start(settings);
   }
diff --git a/lib/src/sip_ua_helper.dart b/lib/src/sip_ua_helper.dart
index a9f138c0..ac2a4de8 100644
--- a/lib/src/sip_ua_helper.dart
+++ b/lib/src/sip_ua_helper.dart
@@ -163,6 +163,7 @@ class SIPUAHelper extends EventManager {
         uaSettings.sessionTimersRefreshMethod;
     _settings.instance_id = uaSettings.instanceId;
     _settings.registrar_server = uaSettings.registrarServer;
+    _settings.contact_uri = uaSettings.contact_uri;
 
     try {
       _ua = UA(_settings);
@@ -749,6 +750,7 @@ class UaSettings {
   String? displayName;
   String? instanceId;
   String? registrarServer;
+  String? contact_uri;
 
   TransportType? transportType;